Externally adjustable voltage regulator having permanent magnet control



Aprll 5, 1966 A. E. BEATY EXTERNALLY ADJUSTABLE VOLTAGE REGULATOR HAVINGPERMANENT MAGNET CONTROL Flled June 26 1965 PERMANENT MA GNET INVENTOR.ALLEN E BEATY BY QW A TTOR/VE United States Patent Office 3,244,945Patented Apr. 5, 1966 EXTERNALLY ADJUSTABLE VOLTAGE REG- ULATOR HAVINGPERMANENT MAGNET CONTROL Allen E. Beaty, Anderson, llnd., assignor toGeneral Motors Corporation, Detroit, Mich., a corporation of DelawareFiled June 26, 1963, Ser. No. 290,655 4 Claims. (Cl. 317172) Thisinvention relates to voltage regulators and more particularly to avoltage regulator which has an external adjustment means for adjustingthe amount of voltage required to move the armature of a voltageregulating relay.

In voltage regulators of the vibrating contact type, it is at timesnecessary to remove the cover of the regulator in order to adjust thespring tension which biases the armature of the voltage regulating relayin one direction. This adjustment is required in order to adjust theoutput voltage of a generator which is being regulated by the voltageregulator. p

The present invention in contrast to an arrangement wherein theregulator cover must be removed to adjust the voltage regulating relayis concerned with a means for externally adjusting the voltageregulating relay without the necessity of removing the cover.

External adjustment for voltage regulating relays has been accomplishedin the past by devices which require the shifting of a conductive screwbetween different positions to regulate a tapped type of resistor.Another method is illustrated in the patent to Heath, 2,869,051, inwhich a flux shunting device can be externally adjusted to adjust thevoltage regulator.

In contrast to the device shown in the Heath patent and in contrast toexternal adjustment devices which require the shifting of a conductivescrew, it is an object of this invention to provide an adjustment devicefor an electromagnetic relay which includes a permanent magnet that canbe shifted to aid or oppose the flux flowing between the core of theelectromagnet and the armature.

Another object of this invention is to provide :an adjustment device fora relay wherein a permanent magnet is rotatably supported by the coverof the relay and is located in such a position that the flux traversingthe air gap between the core of the relay and the armature can be aidedor opposedby the flux of the permanent magnet. With this arrangement, itis possible to replace existing covers on regulating relays with a newcover which has the rotatable permanent magnet to provide an externaladjustment means for an existing regulating relay. I

Further objects and advantages of the present invention will be apparentfrom the following description, reference being bad to the accompanyingdrawings wherein preferred embodiments of the present invention areclearly shown.

In the drawings:

FIGURE 1 is an end view of a voltage regulating relay having theexternal adjustment means of this invention.

FIGURE 2 is an enlarged sectional view taken along line 22 of FIGURE 1.

FIGURE 3 is a view taken along line 33 of FIG- URE 2.

FIGURE 4 is a perspective view showing the relative positions of thepermanent magnet and the regulating relay.

Referring now to the drawings, the reference numeral generallydesignates a base of a conventional voltage regulating relay. This relaymay be of a so-called double contact type which is shown in the patentto Heath, 2,920,160. The relay includes the usual magnetic core (notillustrated) which is attached to a pole piece 12 formed of magneticmaterial and which is secured to the base 10 as by a rivet 14. The coreis surrounded by a conventional c-oil winding 16. The rivet 14 serves tohold a U-shaped member 18 in place which is sometimes termed as theheel-iron of the relay.

The armature for the relay is generally designated by reference numeral20. This armature includes the part 22 which is pivotally secured to oneend of the leg 18a of the frame 18 by a conventional flat spring hinge24. The magnetic part 22 carries an electrical contact 26 whichcooperates with a fixed contact 28 carried by a spring arm 30. The endof the arm (not shown) in FIG- URE 2 can be supported by the base of therelay and this arm 30 carries another fixed contact 32. The arm 30 whichcarries the fixed contacts 28 and 32 can be adjusted vertically byrotating a plastic part 34 which is threaded on to a screw 36 carried bythe leg 18b of the relay frame 18. It will be appreciated that thecontacts 26 and 28 open and close as the armature 20 is moved.

The armature 20 carries another metal part 38 which is engaged by oneend of a spring 39 to urge the armature 20 upwardly in FIGURE 4. Thepart 38 carries a contact 40 which cooperates with the fixed contact 32.The part 38 is insulated from the part 22 by the insulators 42 and 44.

When the coil winding 16 is energized, flux is generated in the core ofthe coil winding and flux can flow through the core, through the frame18, :then through the portion 22 of the armature and then across the airgap to the pole piece 12 and back to the opposite side of the core forthe coil winding, This flux tends to cause the part 22 of the armatureto move toward the pole piece 12 in a manner well known to those skilledin the art and this movement is opposed by the spring 39.

The present invention is concerned with an external adjustment means foraiding or opposing the flux transversing the air gap between the part 22of the armature and the top of pole piece 12. To this end, the cover 50of the voltage regulator is provided with a permanent magnet 52 which isformed to provide arcuate segments 54 and 56. The permanent magnet 52can be of the ferrite type and is magnetized, for example, such that thearcuate segment 54 is a north pole and the arcuate segment 56 is a southpole.

The permanent magnet 52 is adjusted by moving a knob 58 which is formed,for example, of plastic material. The knob 58 has an axially projectingsection 60 which passes through an opening in the permanent magnet 52.The knob SS engages a plastic part or rotatable support 62 fitted in anopening formed in the cover 50 having a detent projection 64 which cansnap into depressions 66 formed in the cover 50. The permanent magnet isheld in place by a-spring clip 68 having tang sections 68a and 68b whichgrip the portion 60 of the knob 58 when the spring clip is pushed on tothe portion 60. The spring clip fits within slots 70 formed in thepermanent magnet that separate the arcuate sections 54 and 56 and thespring clip therefore serves to hold the permanent magnet in place andalso to rotatably drive the permanent magnet. The spring clip 68 is alsolocated within slots 72 formed in the plastic part 62 so that the springclip rotatably drives the plastic part 62. The detent projection 64 cansnap into the depressions 66 of the cover 50 as it is rotated.

Although a specific means has been disclosed for sup porting androtatably driving the rotatable magnet, it will be appreciated thatvarious other means could be provided to accomplish the same purpose.

In order to understand the function of the permanent magnet 52, it willbe appreciated that the amount of pull applied to the part 22 of thearmature 20 will depend upon the amount of flux traversing the air gapbetween the pole piece 12 and the part 22 of the armature. This flux canbe aided or opposed in a varying magnitude by the perma- I nent magnet52 which can be rotated to various positions relative to the part 22 andpole piece 12 of the voltage regulating relay. Thus in certainpositions, the arcuate sections 54 and 56 will be in such a position asto add to the flux traversing the air gap between the pole piece 12 andthe armature part 22. In other positions, the flux provided by thepermanent magnet 22 may still be additive but due to its relativeposition will have less effect. The permanent magnet can be adjustedsuch that its arcuate sections 54 and 56 will oppose the magnetic fluxtraversing the air gap between the pole piece 12 and the armature part22 and to various degrees of opposition.

Where the permanent magnet aids the magnetic flux provided by the coilwinding 16, it will be appreciated that it will require less magneticflux by the coil winding 16 to move the armature part 22 toward the polepiece 12. On the other hand, where the permanent magnet opposes themagnetic flux traversing the air gap between part 22 and the pole piece12, it will take a greater magnetic flux generated by the coil winding16 to pull the armature part downwardly. In this manner, the voltageregulating relay can be externally adjusted to provide the desiredoutput voltage for the generator that it regulates. Thus where theoutput voltage of the generator is too high, the permanent magnet isadjusted in such a direction as to aid the magnetic flux traversing theair gap between armature part 22 and pole piece 12 and where thegenerator voltage is too low, the permanent magnet is adjusted to opposethis flux.

While the embodiments of the present invention as herein disclosedconstitute a preferred form, it is to be understood that other formsmight be adopted.

What is claimed is as follows:

1. A relay comprising a coil winding, an armature, a magnetic circuitincluding an air gap and said armature for flux generated by said coilwinding, a cover member for said relay, a rotatable support having aportion fitting within an opening formed in said cover member, saidsupport having a detent means which is adapted to snap into depressionsformed in said cover member, an actuating knob having a projectingportion passing through said support, a permanent magnet located Withinsaid cover having a central opening receiving said projecting portion ofsaid actuating knob, and a spring clip for holding said permanent magnetwith respect to the projecting portion of said actuating knob, saidspring clip fitting, within slots formed in said support and in saidpermanent magnet, said permanent magnet being located adjacent said airgap to aid or oppose the fiux generated by said coil winding whichtraverses said air gap.

2. A relay comprising a base, a cover secured to said base, said coverand base defining a compartment, a coil winding in said compartment forgenerating magnetic flux, an armature located within said compartmentshiftable toward said coil winding under the influence of said magneticflux, and a permanent magnet adjustable relative to and supported bysaid cover member for aiding or opposing the magnetic flux generated bysaid coil winding, said permanent magnet being located within saidcompartment, and means external of said compartment connected with saidpermanent magnet for adjusting said permanent magnet, said permanentmagnet being spaced from said armature and coil winding to provide anair gap between said magnet and said armature and coil winding.

3. An electromagnetic relay comprising a base, a cover secured to saidbase, said base and cover defining a compartment, a magnetic corelocated in said compartment, a coil winding wound on said magnetic core,an armature in said compartment, a magnetic circuit for said relayincluding an air gap located between said core and said armature, and apermanent magnet having a pair of pole faces of opposite magneticpolarity located at one side of said air gap, said permanent magnetbeing located in said compartment and supported by said cover, saidpermanent magnet being adjustable to aid or oppose the flux passingthrough said air gap generated by current flow through said coilWinding, said pole faces being located in a plane which is substantiallynormal to the plane of said armature, said pole faces being spaced fromsaid core and armature to provide an air gap between said pole faces andsaid core and armature.

4. In combination, a cover for an electromagnetic relay, an actuatingknob located externally of said cover having a section passing throughan opening in one wall of said cover, a spring clip fixed to a portionof said actuating knob, and a permanent magnet located within said coverhaving a slot defined by a pair of side walls extending from a bottomwall, said spring clip being located within said slot and engaging theside walls of said slot for rotatably driving said permanent magnet,said spring clip engaging said bottom Wall of said slot to hold saidpermanent magnet in place axially relative to said knob.

References Cited by the Examiner UNITED STATES PATENTS 252,497 1 /1882Mott 317-176 2,321,157 6/1943 Rees -36 2,369,380 2/ 1945 Tinnerman 85-36X 2,673,263 3/1954 Casey 317-171 X 2,892,187 6/1959 Bredehoft 317-l77 X2,920,160 1/1960 Heath 20087 2,972,038 2/ 1961 Gomersall 20087 X FOREIGNPATENTS 235,643 9/1961 Australia. 1,258,367 3/1961 France.

JOHN F. BURNS, Primary Examiner. LARAM'IE E. ASKIN, Examiner.

4. IN COMBINATION, A COVER FOR AN ELECTROMAGNETIC RELAY, AN ACTUATINGKNOB LOCATED EXTERNALLY OF SAID COVER HAVING A SECTION PASSING THROUGHAN OPENING IN ONE WALL OF SAID COVER, A SPRING CLIP FIXED TO A POSITIONOF SAID ACTUATING KNOB, AND A PERMANENT MAGNET LOCATED WITHIN SAID COVERHAVING A SLOT DEFINED BY A PAIR OF SIDE WALLS EXTENDING FROM A BOTTOMWALL, SAID SPRING CLIP BEING LOCATED WITHIN SAID SLOT AND ENGAGING THESIDE WALLS OF SAID SLOT FOR ROTATABLY DRIVING SAID PERMANENT MAGNET,SAID SPRING CLIP ENGAGING SAID BOTTOM WALL OF SAID SLOT TO HOLD SAIDPERMANENT MAGNET IN PLACE AXIALLY RELATIVE TO SAID KNOB.